In order to succeed you must fail, so that you know what not to do the next time - Anthony J. D'Angelo
Despite people's tendency to overshare on social media, Facebook Beacon was a step too far. The product was a means for the site to track what users bought online, then share that information with advertisers so ads could target the user's preferences. However, it tracked online shopping habits even when users weren't logged on to Facebook, prompting a privacy outcry.
On Dec. 5, 2007, Mark Zuckerberg released a statement about Beacon, saying Facebook had "missed the right balance" when creating it. The feature was shut down soon after.